1. Chapter 6: Nomenclature Formulas Describe Compounds
H2O
Water: 2 Hydrogen atoms and 1 Oxygen atom
C12H22O11
Sucrose (table sugar):
12 atoms of Carbon, 22 atoms of Hydrogen and 11 atoms Oxygen

2. Chapter 6: Nomenclature
If the molecule is an ion a superscript number represents the charge of the molecule
A number in front of a molecule means that you have more than one molecule; it is often referred to as coefficient
4 Mg(NO3) 2
A subscript number after a parenthesis means that all the atoms in the parenthesis are present in that molecule multiple times.
A subscript number after an element means that you have more than 1 atom for that element

3. Order of Elements in a Formula
metals written first
NaCl
nonmetals written in order from Table 5.1
CO2
occasional exceptions for historical or informational reasons
H2O, but NaOH
Table 5.1
Order of Listing Nonmetals
in Chemical Formulas C P N H S I Br Cl O F

4. Classifying Materials
atomic elements = elements whose particles are single atoms
molecular elements = elements whose particles are multi-atom molecules
molecular compounds = compounds whose particles are molecules made of only nonmetals
ionic compounds = compounds whose particles are cations and anions

5. Molecular Elements H2 N2 O2 F2 Cl2 Br2 I2
Certain elements occur as 2 atom molecules
Rule of 7’s
there are 7 common diatomic elements
find the element with atomic number 7, N
make a figure 7 by going over to Group 7A, then down
don’t forget to include H2
VIIA 7 H2
N2 O F2
Cl2
Br2 I2

6. Molecular Compounds
two or more nonmetals
smallest unit is a molecule

7. Ionic Compounds metals + nonmetals
no individual molecule units, instead have a 3-dimensional array of cations and anions made of formula units

8. Molecular View of Elements and Compounds

9. Step1 - Common Names - Exceptions
H2O = water, steam, ice
NH3 = ammonia
CH4 = methane
NaCl = table salt
C12H22O11 = table sugar

10. Step 2 - Classifying Compounds
Compounds containing a metal and a nonmetal = binary ionic
Type I and II
Compounds containing a polyatomic ion = ionic with polyatomic ion
Compounds containing two nonmetals = binary molecular compounds
Compounds containing H and a nonmetal = binary acids
Compounds containing H and a polyatomic ion = oxyacids

11. Step 3 - Formula-to-Name Rules for Ionic
Made of cation and anion
Name by simply naming the ions
If cation is:
Type I metal = metal name
Type II metal = metal name(charge)
Polyatomic ion = name of polyatomic ion
If anion is:
Nonmetal = stem of nonmetal name + ide

12. Monatomic Nonmetal Anion
determine the charge from position on the Periodic Table
to name anion, change ending on the element name to –ide
4A = -4
5A = -3
6A = -2
7A = -1
C = carbide
N = nitride
O = oxide
F = fluoride
Si = silicide
P = phosphide
S = sulfide
Cl = chloride

13. How do you know a metal cation is Type II?
Metal Cations
Type I
metals whose ions can only have one possible charge
IA, IIA, (Al, Ga, In)
determine charge by position on the Periodic Table
IA = +1, IIA = +2, (Al, Ga, In = +3)
Type II
metals whose ions can have more than one possible charge
determine charge by charge on anion
How do you know a metal cation is Type II?
its not Type I !!!

14. Type I Binary Ionic Compounds
Contain Metal Cation + Nonmetal Anion
Metal listed first in formula & name
name metal cation first, name nonmetal anion second
cation name is the metal name
nonmetal anion named by changing the ending on the nonmetal name to -ide

15. Type II Binary Ionic Compounds
Contain Metal Cation + Nonmetal Anion
Metal listed first in formula & name
name metal cation first, name nonmetal anion second
metal cation name is the metal name followed by a Roman Numeral in parentheses to indicate its charge
determine charge from anion charge
Common Type II cations in Table 5.5
nonmetal anion named by changing the ending on the nonmetal name to -ide

16. Some Common Polyatomic Ions
Name
Formula
acetate
C2H3O2–
carbonate
CO32–
hydrogen carbonate
(aka bicarbonate)
HCO3–
hydroxide
OH–
nitrate
NO3–
nitrite
NO2–
chromate
CrO42–
dichromate
Cr2O72–
ammonium
NH4+
Name
Formula
hypochlorite
ClO–
chlorite
ClO2–
chlorate
ClO3–
perchlorate
ClO4–
sulfate
SO42–
sulfite
SO32–
hydrogensulfate
(aka bisulfate)
HSO4–
hydrogensulfite
(aka bisulfite)
HSO3–

17. Step 3- Formula-to-Name Rules for Molecular
we will not learn the rules for molecular compounds with more than 2 elements
for binary molecular:
name first nonmetal
then name second nonmetal with ide ending
then give each name a prefix to indicate its subscript in the formula

18. Binary Molecular Compounds of 2 Nonmetals
Name first element in formula first
use the full name of the element
Name the second element in the formula with an -ide
as if it were an anion, however, remember these compounds do not contain ions!
Use a prefix in front of each name to indicate the number of atoms
Never use the prefix mono- on the first element

19. Subscript - Prefixes 1 = mono-; 2 = di- 3 = tri- 4 = tetra- 5 = penta-
not used on first nonmetal
2 = di-
3 = tri-
4 = tetra-
5 = penta-
6 = hexa-
7 = hepta-
8 = octa-
drop last “a” if name begins with vowel

20. Acids Contain H+1 cation and anion
in aqueous solution
Binary acids have H+1 cation and nonmetal anion
Oxyacids have H+1 cation and polyatomic anion

21. Formula-to-Name Acids
acids are molecular compounds that often behave like they are made of ions
All names have acid at end
Binary Acids = hydro prefix + stem of the name of the nonmetal + ic suffix
Oxyacids
if polyatomic ion ends in –ate = name of polyatomic ion with –ic suffix
if polyatomic ion ends in –ite = name of polyatomic ion with –ous suffix

22. Formula-to-Name Flow Chart

23. Writing the Formulas from the Names
For binary molecular compounds, use the prefixes to determine the subscripts
For Type I, Type II, Ternary Compounds and Acids
Determine the ions present
Determine the charges on the cation and anion
Balance the charges to get the subscripts

24. Compounds that Contain Ions
compounds of metals with nonmetals are made of ions
metal atoms form cations, nonmetal atoms for anions
compound must have no total charge, therefore we must balance the numbers of cations and anions in a compound to get 0 charge
if Na+ is combined with S2-, you will need 2 Na+ ions for every S2- ion to balance the charges, therefore the formula must be Na2S

25. Writing Formulas for Ionic Compounds
Write the symbol for the metal cation and its charge
Write the symbol for the nonmetal anion and its charge
Charge (without sign) becomes subscript for other ion
Reduce subscripts to smallest whole number ratio
Check that the sum of the charges of the cation cancels the sum of the anions

26. Write the formula of a compound made from aluminum ions and oxide ions
Write the symbol for the metal cation and its charge
Write the symbol for the nonmetal anion and its charge
Charge (without sign) becomes subscript for other ion
Reduce subscripts to smallest whole number ratio
Check that the total charge of the cations cancels the total charge of the anions
Al+3 column IIIA
O2- column VIA
Al+3 O2-
Al2 O3
Al = (2)∙(+3) = +6
O = (3)∙(-2) = -6

27. Formula Mass the mass of an individual molecule or formula unit
also known as molecular mass or molecular weight
sum of the masses of the atoms in a single molecule or formula unit
whole = sum of the parts!
mass of 1 molecule of H2O
= 2(1.01 amu H) amu O = amu